When utilized as nucleating agents, divalent metal terephthalate salts are extremely stable up to a temperature of approximately 400.degree. C., insoluble in most solvents, and have very low electrical conductivity. It is s believed that the incorporation of a nucleating agent into a polymer melt might enhance the mechanical properties of the polymer. However, known techniques for the addition of nucleating agents to liquid crystal polymers typically result in nonuniform polymer properties and reduces melt processability.
It is desirable to improve the crystal forming properties of liquid crystal polyesters without significantly reducing the mechanical properties. One essential property influenced by crystal formation is the distortion temperature under a load, i.e., heat distortion temperature. The heat distortion temperature under a load is the temperature above which a polyester can no longer support a useful force with time. A film, fiber or molded article having an improved heat distortion temperature under a load would be more suitable for high heat applications.